Initial implementation of loop-to-call-chain intention

idea/testData/intentions/loopToCallChain/map_variableStillNeeded.kt

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+fun foo(list: List<String>): String? {
+    <caret>for (s in list) {
+        val length = s.length
+        if (length > 0) return s + length
+    }
+    return null
+}